Herbert Valerio Riedel's Theses

Computer Science Diploma Thesis

@MastersThesis{hvriedel-2005-SWUARTS,
author = "Herbert Valerio Riedel",
title = "{Universal Asynchronous Receiver/Transceivers}:
{A Software Implementation Approach}",
school = "Institute of Computer Aided Automation,
Vienna University of Technology",
year = {2005},
month = dec,
address = "Operngasse 9/183, A-1040 Vienna, Austria",
keywords = {Software-UARTs, ISO7816, Smart-cards, RTOS, Linux,
Sofware Peripherals},
abstract = "Universal Asynchronous Receiver/Transmitters (UART) are
hardware components usually required to handle serial
communication protocols; protocols that are widely in
use, ranging from implementing low-cost communication
paths between peripherals on embedded systems to
connecting hosts to external peripherals or other host
systems.
With the continued growth of CPU performance it becomes
viable to emulate UARTs traditionally implemented as
dedicated hardware components in software. Software
implementations allow for more flexibility with respect
to upgrade-ability, potentially shorter time to market,
and cost savings at the expense of higher CPU
utilisation. When the host system is expected to service
other processes while the software UARTs is active,
challenges are faced for the implementation, depending on
the real time constraints imposed by the serial protocol.
This thesis gives an overview of various serial protocols
in use and discusses the difficulties arising when
emulating the corresponding UART in
software. Furthermore, different common software UART
approaches for the implementation of ISO7816 serial
protocol are presented in the context of the general
purpose non-real-time Linux kernel, and discussed with
respect to reliability and (whole system)
performance. Finally, a novel algorithm is presented
which meets the posed requirements of a portable,
response-conserving, reliable, good performing, and
protocol conforming implementation."
}